1. Field of the Invention
The present invention relates to a silver halide color photographic light-sensitive material and, more particularly, to a silver halide color photographic light-sensitive material having good color forming properties and a high color reproducibility.
2. Description of the Related Art
It is common practice to use phenol- or naphthol-based cyan couplers in order to form cyan color images. However, these couplers have undesirable absorption in green- and blue-light regions and hence have a serious problem of impairing the color reproducibilities of particularly blue and green significantly. Therefore, solving this problem has been strongly desired.
As a means for eliminating this problem, 2,4-diphenylimidazole-based cyan couplers are proposed in EP249,453A2. In dyes formed from these couplers, undesirable absorption in green and blue regions is reduced compared to those derived from the phenol- or naphthol-based cyan couplers described above. However, the color reproducibilities of these couplers are still unsatisfactory, and so further improvements have been desired. In addition, these couplers are low in reactivity (i.e., coupling activity) with the oxidized form of a developing agent and have a serious problem that the fastness of the resultant dye against heat and light is very low. For these reasons, these couplers cannot be put into practical use as they are.
Pyrazoloazole-based cyan couplers described in JP-A-64-552 ("JP-A" means Published Unexamined Japanese Patent Application), JP-A-64-553, JP-A-64-554, JP-A-64-555, JP-A-64-556, and JP-A-64-557 are reduced in undesirable absorption in green and blue regions compared to conventional dyes, but the color reproducibilities of these couplers are still insufficient. In addition, these couplers are very poor in color forming properties.
EP456,226A1 discloses a pyrrolopyrazole-based cyan coupler as a coupler capable of yielding dyes excellent in hue. Although this coupler is improved compared to the above cyan couplers in terms of color reproducibility, this improvement is still unsatisfactory, and yet the coupler has a drawback of a large color fog in an unexposed region. Furthermore, the coupler does not reach a satisfactory level also in terms of color forming properties.
Couplers having a 1H-pyrrolo[1,2-b][1,2,4]triazole nucleus are described in Japan Photographic Society Annual Meeting 1985 (at Private College Hall, 23rd and 24th of May, 1985), the Substances of Lectures, pages 108 to 110, JP-A-62-279340, and JP-A-62-278552. All of these couplers are known as magenta couplers. Absorption spectrums of dyes formed from the pyrrolotriazole-based couplers described in Japan Photographic Society, the Substances of Lectures are slightly wider than those of dyes formed from well-known pyrazolotriazole-based magenta couplers. That is, the hues of these couplers are unsatisfactory even as a magenta coupler.
Although couplers having a pyrrolotriazole nucleus are also described in JP-A-62-291646 and JP-A-63-32548, all these couplers are limited to couplers for forming magenta dyes.
On the other hand, various attempts have been made to adjust an absorption wavelength of the formed dye by combining a coupler with a high boiling point organic solvent as a dispersion medium of the coupler. For example, JP-A-1-118131, JP-A-1-156745, and JP-A-2-135442 disclose methods of shifting the absorption wavelength to a longer wavelength side by using phosphoric ester-based high boiling point organic solvents for a pyrazolotriazole-type cyan coupler, an imidazole-type cyan coupler, and a 5,6-fused ring pyrazole-type cyan coupler, respectively, thereby obtaining a more favorable hue. However, since the shifting of wavelength obtained by these methods are small, the effects of the methods are still insufficient.
Examples of a method using phosphonic esters, phosphinic esters, or phosphine oxides in order to improve hue are described in, e.g., JP-A-56-19049, JP-A-63-301941, and JP-A-2-4239. These methods are used primarily to shorten the wavelength at the absorption edge on the long-wavelength side of a yellow coupler or a magenta coupler.
Under the present conditions, however, no sufficiently satisfactory cyan dyes have been obtained yet even by applying the above methods to conventionally known cyan couplers, and so a strong demand has arisen for further improvements.